IMS (IP Multimedia Subsystem) is a set of standards providing the signalling, delivery, authentication and billing functions necessary for real-time, packet-based calls and services across virtually any underlying network technology. In other words, IMS is a platform adapted for an efficient and rapid implementation of next-generation IP services in both fixed and mobile networks which will accelerate the convergence of fixed and wireless networks.
A common description of a driving vision behind IMS is the focus on giving subscribers consistent, converged services in daily life communication, involving the concept of “one handset device, one address book, one email address, and one bill” from all service sessions across all networks, comprising traditional telephony, as well as Internet communication over all wire-line and wireless transports.
Normally, IMS subscribers have a plurality of IMS operators to choose from, each having different services and prices to offer. Typically an IMS subscriber has a business agreement with one of the IMS operators operating on the market. From the IMS subscribers' point of view, however, it is desirable to have access to a wider range of service than what can be offered by one chosen IMS operator. In order to be able to satisfy its subscribers, IMS operators often have mutual business agreements with each other, whereby one IMS operator can offer or make use of another IMS operators services.
FIG. 1 illustrates one way of delivering services from a third party service provider 103 to a user of a mobile station 100 over IMS, according to the prior art. The user of mobile station 100 is a subscriber of a first IMS operator managing an IMS network 101. The first IMS operator, however, do not have any direct business relation with the third party service provider 103, and, thus, it is not obvious that the mobile station 100 can access services from the third party service provider 103 via IMS network 101.
The third party service provider 103 has a business relation with a second operator, managing a second IMS network 102. The user of the mobile station 100 activates an application 104, which recognises a requirement for a service, which cannot be accessed from IMS network 101, but which is accessible from the third party service provider 103. A necessary condition for the first operator to be able to offer this service to the user of mobile station 100 is that the first IMS operator has an interconnection agreement with the second IMS operator. In such a situation, the mobile station 100 may set up an IMS session with the third party service provider 103, by first connecting with the first operators IMS network 101 in a step 1:1. The first operator of IMS network 101, having an interconnection agreement with the second operator of IMS network 102, sets up an interconnection between the two IMS networks in a second step 1:2, and the second operator completes the IMS session by connecting to the third party service provider 103 in a third step 1:3. After having completed the signalling (not shown), verifying a successful IMS session set up from the third party service provider 103, the application 104 of the mobile station 100 may access services, provided from an application 105 of the third party service provider 103, via the IMS session in a final step 1:4.
In another scenario, a third party service provider wanting to enhance its service offering may have a requirement to be able to access certain services from one or more network operators, other than its own operator. In order to do so there has to be a business agreement between the two service providers. Such network services may include, e.g. user statistics, location information or control of communication quality (QoS), and may be provided via standardised or published interfaces, such as e.g. parlay or different types of web services.
A prior art scenario illustrating this type of situation will now be described with reference to FIG. 2, wherein a third party service provider 203, providing services to a user of a mobile station 200, via a first network 206 wants to enhance its services by using an additional network service provided from an IMS network 201 of a first operator. A user of mobile station 200 has initiated an application 204, which requires a service, accessible from the third party service provider 203. Initially, the application 204 of the mobile station 200 establishes a connection with an application 205 of the third party service provider 103 in a first step 2:1, via the first network 206. In a next step 2:2, the application 105, recognising a requirement for a network service which cannot be provided from the third party service provider, but from the IMS network 201 of the first operator. The application 205, therefore, establishes a connection with IMS network 201, after which the required network service can be accessed and used by the application 205. In order for the third party service provider to be able to access the required service from the IMS network 201 of the first operator, however, the third service provider 203 has to have a business relation with the first operator.
As mentioned in both prior art scenarios presented above, it is necessary to have established a business relation between two parties if they are to be able to use each other's services, and thereby be able to provide an enhanced range of services to its subscribers.
FIG. 3 illustrates how different business agreements can be set up between a first operator, managing a first IMS network 301, a second operator, managing a second IMS network 302, a user of a mobile station 300, and a third party service provider 303, i.e. the participants presented in FIG. 1.
In FIG. 3, the user of mobile station 300 is a subscriber of the operator of IMS network 301, and, thus, a business agreement 304, defined as a subscription, is established between these two parties.
In the figure, the first operator of IMS network 301 also has a business relation 305, defined as an interconnection agreement with the second operator of IMS network 302. As an alternative to a direct interconnection agreement between the first IMS network 301 and the second IMS network 302, a business relation may be set up between the two IMS networks via a transit network (not shown), which may have an interconnection agreement with both IMS networks.
The third party service provider 303 may have another business relation 306 with the second IMS operator to use the second IMS network 302. In addition, the figure illustrates that the user of the mobile station 300 also may have a business relation 307 set up directly with the third party service provider 303, via a separate network 308.
Failure for parties to get access to network services offered by certain operators may obstruct an operator from being able to offer competitive services to its subscribers, and may also become an obstacle for the operator in the development of new services. Creation of business relations with all major operators will, however, require great efforts from the operators and third party service providers involved.